Side effects
Redness or itching where I inject Zepbound: is that normal?
Yes, it is a listed common side effect: 6 to 8 percent of people on Zepbound in the trials against 2 percent on placebo, more often with antibodies to tirzepatide. A serious allergic reaction is different: stop and get help.
The Oolite team, from the FDA labels
Sources checked Oct 27, 2026
Published Nov 7, 2026
Updated Oct 27, 2026 · 3 min read
The short answer
Yes, it is a listed common side effect: 6 to 8 percent of people on Zepbound in the trials against 2 percent on placebo, more often with antibodies to tirzepatide. A serious allergic reaction is different: stop and get help.
What the label says
The first page of the prescribing information lists them among the most common side effects:
From the labelThe most common adverse reactions, reported in ≥5% of patients treated with ZEPBOUND are: nausea, diarrhea, vomiting, constipation, abdominal pain, dyspepsia, injection site reactions, fatigue, hypersensitivity reactions, eructation, hair loss, gastroesophageal reflux disease.
The side effects table in §6.1 gives the numbers from the two main trials: injection site reactions in 2 percent of people on placebo, and in 6, 8 and 8 percent of people on 5 mg, 10 mg and 15 mg. The label counts them as one line; it does not split them into redness, itching or swelling in the text. The Medication Guide lists them in plain words among the most common side effects.
Then a sentence that explains who gets them more:
From the labelIn ZEPBOUND-treated patients in a pool of Study 1 and 2, injection site reactions were more frequent in those with anti-tirzepatide antibodies (11.3%) compared to those who did not develop anti-tirzepatide antibodies (1%).
What the antibodies mean
Antibodies against tirzepatide were common in the trials: the immunogenicity section (§12.6) reports them in most of the people treated. They are linked to more skin reactions at the spot, and to more allergic type reactions in general. What they did not change is spelled out:
From the labelNo clinically significant effect of anti-tirzepatide antibodies on pharmacokinetics or effectiveness of ZEPBOUND has been identified.
So a red, itchy spot is not a sign that the dose was lost. It is a known reaction, in a minority of people, and the label treats it as such.
The label also notes that most hypersensitivity reactions in the trials were on the skin:
From the labelThe majority of the hypersensitivity reactions in trials were skin reactions (e.g., rash, itching).
When it is something else
A reaction that stays where the shot went is one thing. A reaction of the whole body is another, and the Medication Guide is direct about it. Stop using Zepbound and get medical help right away if you have signs of a serious allergic reaction: swelling of your face, lips, tongue or throat; problems breathing or swallowing; a severe rash or itching; fainting or feeling dizzy; a very rapid heartbeat.
Between the two, a spot that keeps reacting week after week, or one that gets worse, is worth showing to your prescriber.
Rotation, and why
The Medication Guide asks for a new spot every week:
From the labelChange (rotate) your injection site with each weekly injection. You may use the same area of your body but be sure to choose a different injection site in that area. Do not use the same site for each injection.
The Instructions for Use for the single dose vial give the reason:
From the labelChange (rotate) your injection site within the area you choose for each dose to reduce your risk of getting lipodystrophy (pits in skin or thickened skin) and localized cutaneous amyloidosis (skin with lumps) at the injection sites.
They also say where not to inject:
From the labelDo not inject where the skin is tender, bruised, scaly or hard, or into scars or damaged skin.
How to give the shot itself is in the Instructions for Use of your device and in the training from your healthcare provider.
Oolite's shot log has an "At the spot" line, so a reaction is kept with its date and the place it happened, and the report for your prescriber shows whether it follows one site.
Questions people ask
How common is it?
In the two main trials, injection site reactions were reported by 6 percent of people on 5 mg, 8 percent on 10 mg and 8 percent on 15 mg, against 2 percent on placebo. The label lists them among the side effects seen in at least 5 percent of people.
Does a reaction mean the shot did not work?
The label links reactions to antibodies against tirzepatide, and says no clinically significant effect of those antibodies on how the drug is absorbed or how well it works has been identified.
When is it more than a skin reaction?
The Medication Guide asks you to stop Zepbound and get medical help right away for signs of a serious allergic reaction: swelling of the face, lips, tongue or throat, trouble breathing or swallowing, severe rash or itching, fainting or feeling dizzy, a very rapid heartbeat.
Should I avoid that spot next week?
The Medication Guide asks you to change the injection site every week anyway, and the vial instructions say not to inject where the skin is tender, bruised, scaly or hard.
Sources
- Zepbound prescribing information, Eli Lilly, Highlights, §6.1 and §12.6, revised 8/2026 · Injection site reactions among adverse reactions in at least 5 percent; Table 1: 2 percent placebo, 6, 8 and 8 percent at 5, 10 and 15 mg; 11.3 vs 1 percent with and without anti-tirzepatide antibodies; no clinically significant effect of antibodies on pharmacokinetics or effectiveness identified; most hypersensitivity reactions were skin reactions.
- Zepbound Medication Guide, Eli Lilly, ZEP-0010-MG-20260828 · Rotate the injection site with each weekly injection; signs of a serious allergic reaction; injection site reactions among the most common side effects.
- Zepbound single dose vial Instructions for Use, Eli Lilly, revised April 2026 · Rotate within the area to reduce the risk of lipodystrophy and localized cutaneous amyloidosis; do not inject where the skin is tender, bruised, scaly or hard.
Sources checked Oct 27, 2026. This page is information, not medical advice: read the medical disclaimer, and talk to your prescriber or pharmacist about your own treatment.
Written by
The Oolite team, from the FDA labels
We make Oolite. Every answer starts from the FDA prescribing information, quoted word for word, and is rewritten when a label changes.
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